The Microstructure, Hardness, Phase Transformation and Mechanical Properties of a NiTi Coating Applied to Graphite Substrate via a Plasma Spraying Process

Abstract

In this study, Ni50Ti50 powder was coated on the surface of graphite substrate (C) via a plasma spraying process using a radio frequency inductively coupled plasma reactor. The coating was carried out using 12- and 9-kW power under Ar atmosphere. The cross-section of coating layers and the surface were examined with Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectrum (EDX), and X-ray Diffractometer (XRD) analyses and microhardness test. The thickness and quality of the coating increased with the input power. Many pores were detected in the cross-sectional surface areas. Higher input power caused a better coating layer of NiTi alloy. The hardness of the coating layer decreases with higher input power.

Evaluation of Microstructure–Porosity–Hardness of Thermal Plasma-Sprayed NiTi Coating Layers

“…The materials' performance will be enriched with a thin coating layer of NiTi added to the surface as a protective barrier against corrosion and erosion issues. The coating could be achieved through powder metallurgical routes using the thermal plasma-spraying method [4,5]. Thermal plasma spraying has emerged as a potential method for both the deposition of coatings and the fabrication of parts from metals and alloy powders.…”